Expression of the Floral Repressor miRNA156 is Positively Regulated by the AGAMOUS-like Proteins AGL15 and AGL18

The regulation of flowering time has crucial implications for plant fitness. MicroRNA156 (miR156) represses the floral transition in Arabidopsis thaliana, but the mechanisms regulating its transcription remain unclear. Here, we show that two AGAMOUS-like proteins, AGL15 and AGL18, act as positive re...

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Main Authors:	Serivichyaswat, Phanu, Ryu, Hak-Seung, Kim, Wanhui, Kim, Soonkap, Chung, Kyung Sook, Kim, Jae Joon, Ahn, Ji Hoon
Format:	Online
Language:	English
Published:	Korean Society for Molecular and Cellular Biology 2015
Online Access:	https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4363726/

id	pubmed-4363726
recordtype	oai_dc
spelling	pubmed-43637262015-03-27 Expression of the Floral Repressor miRNA156 is Positively Regulated by the AGAMOUS-like Proteins AGL15 and AGL18 Serivichyaswat, Phanu Ryu, Hak-Seung Kim, Wanhui Kim, Soonkap Chung, Kyung Sook Kim, Jae Joon Ahn, Ji Hoon Article The regulation of flowering time has crucial implications for plant fitness. MicroRNA156 (miR156) represses the floral transition in Arabidopsis thaliana, but the mechanisms regulating its transcription remain unclear. Here, we show that two AGAMOUS-like proteins, AGL15 and AGL18, act as positive regulators of the expression of MIR156. Small RNA northern blot analysis revealed a significant decrease in the levels of mature miR156 in agl15 agl18 double mutants, but not in the single mutants, suggesting that AGL15 and AGL18 co-regulate miR156 expression. Histochemical analysis further indicated that the double mutants showed a reduction in MIR156 promoter strength. The double mutants also showed reduced abundance of pri-miR156a and pri-miR156c, two of the primary transcripts from MIR156 genes. Electrophoretic mobility shift assays demonstrated that AGL15 directly associated with the CArG motifs in the MIR156a/c promoters. AGL18 did not show binding affinity to the CArG motifs, but pull-down and yeast two-hybrid assays showed that AGL18 forms a heterodimer with AGL15. GFP reporter assays and bimolecular fluorescence complementation (BiFC) showed that AGL15 and AGL18 co-localize in the nucleus and confirmed their in vivo interaction. Overexpression of miR156 did not affect the levels of AGL15 and AGL18 transcripts. Taking these data together, we present a model for the transcriptional regulation of MIR156. In this model, AGL15 and AGL18 may form a complex along with other proteins, and bind to the CArG motifs of the promoters of MIR156 to activate the MIR156 expression. Korean Society for Molecular and Cellular Biology 2015-03-31 2015-01-30 /pmc/articles/PMC4363726/ /pubmed/25666346 http://dx.doi.org/10.14348/molcells.2015.2311 Text en © The Korean Society for Molecular and Cellular Biology. All rights reserved. This is an open-access article distributed under the terms of the Creative Commons Attribution-NonCommercial-ShareAlike 3.0 Unported License. To view a copy of this license, visit http://creativecommons.org/licenses/by-nc-sa/3.0/.
repository_type	Open Access Journal
institution_category	Foreign Institution
institution	US National Center for Biotechnology Information
building	NCBI PubMed
collection	Online Access
language	English
format	Online
author	Serivichyaswat, Phanu Ryu, Hak-Seung Kim, Wanhui Kim, Soonkap Chung, Kyung Sook Kim, Jae Joon Ahn, Ji Hoon
spellingShingle	Serivichyaswat, Phanu Ryu, Hak-Seung Kim, Wanhui Kim, Soonkap Chung, Kyung Sook Kim, Jae Joon Ahn, Ji Hoon Expression of the Floral Repressor miRNA156 is Positively Regulated by the AGAMOUS-like Proteins AGL15 and AGL18
author_facet	Serivichyaswat, Phanu Ryu, Hak-Seung Kim, Wanhui Kim, Soonkap Chung, Kyung Sook Kim, Jae Joon Ahn, Ji Hoon
author_sort	Serivichyaswat, Phanu
title	Expression of the Floral Repressor miRNA156 is Positively Regulated by the AGAMOUS-like Proteins AGL15 and AGL18
title_short	Expression of the Floral Repressor miRNA156 is Positively Regulated by the AGAMOUS-like Proteins AGL15 and AGL18
title_full	Expression of the Floral Repressor miRNA156 is Positively Regulated by the AGAMOUS-like Proteins AGL15 and AGL18
title_fullStr	Expression of the Floral Repressor miRNA156 is Positively Regulated by the AGAMOUS-like Proteins AGL15 and AGL18
title_full_unstemmed	Expression of the Floral Repressor miRNA156 is Positively Regulated by the AGAMOUS-like Proteins AGL15 and AGL18
title_sort	expression of the floral repressor mirna156 is positively regulated by the agamous-like proteins agl15 and agl18
description	The regulation of flowering time has crucial implications for plant fitness. MicroRNA156 (miR156) represses the floral transition in Arabidopsis thaliana, but the mechanisms regulating its transcription remain unclear. Here, we show that two AGAMOUS-like proteins, AGL15 and AGL18, act as positive regulators of the expression of MIR156. Small RNA northern blot analysis revealed a significant decrease in the levels of mature miR156 in agl15 agl18 double mutants, but not in the single mutants, suggesting that AGL15 and AGL18 co-regulate miR156 expression. Histochemical analysis further indicated that the double mutants showed a reduction in MIR156 promoter strength. The double mutants also showed reduced abundance of pri-miR156a and pri-miR156c, two of the primary transcripts from MIR156 genes. Electrophoretic mobility shift assays demonstrated that AGL15 directly associated with the CArG motifs in the MIR156a/c promoters. AGL18 did not show binding affinity to the CArG motifs, but pull-down and yeast two-hybrid assays showed that AGL18 forms a heterodimer with AGL15. GFP reporter assays and bimolecular fluorescence complementation (BiFC) showed that AGL15 and AGL18 co-localize in the nucleus and confirmed their in vivo interaction. Overexpression of miR156 did not affect the levels of AGL15 and AGL18 transcripts. Taking these data together, we present a model for the transcriptional regulation of MIR156. In this model, AGL15 and AGL18 may form a complex along with other proteins, and bind to the CArG motifs of the promoters of MIR156 to activate the MIR156 expression.
publisher	Korean Society for Molecular and Cellular Biology
publishDate	2015
url	https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4363726/
_version_	1613200009353756672

Expression of the Floral Repressor miRNA156 is Positively Regulated by the AGAMOUS-like Proteins AGL15 and AGL18

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